Slip-ring arrangement especially for brake slippage control installations of motor vehicles

ABSTRACT

A slip-ring arrangement, intended especially for brake force control systems in motor vehicles, for the transmission of electrical signals from a rotating part to a stationary part whereby a signal transmitter is arranged at the rotating part and is connected by way of a line with a slip-ring disposed on the wheel hub on the inside of the brake; one of several stationary brushes slide on the slip-ring whereby the slip-ring itself is arranged on the wheel hub exclusively on the inside of a sealedoff space and is connected with the signal transmitter by way of a cable on the inside of the wheel hub while the brush or brushes are secured at the brake carrier with the aid of a one-piece plastic part which simultaneously contains means for guiding the cable.

Wiirner et al.

SLIP-RING ARRANGEMENT ESPECIALLY FOR BRAKE SLIPPAGE CONTROLINSTALLATIONS OF MOTOR VEHICLES Inventors: Otto Wiirner, Reutlingen;Franz Brugger; Erwin Weller, both of Stuttgart, all of Germany DaimlerBeng Aktiengesellschaft, Stuttgart-Unterukheim, Germany Filed: Sept. 3,1971 Appl. No.: 177,649

Assignee:

Foreign Application Priority Data Sept. 4, 1970 Germany ..P 20 43 841.9

References Cited UNITED STATES PATENTS 4/1953 Branechofsky ..73/ 129 1March 6, 1973 3,162,835 12/1964 Dudar ..339/3RX 2,523,594 9/1950Sagaseretal ..340/58x Primary Examiner-Richard E. Moore Attorney-Craig,Antonelli & Hill A slip-ring arrangement, intended especially for brakeforce control systems in motor vehicles, for the transmission ofelectrical signals from a rotating part to a stationary part whereby asignal transmitter is arranged at the rotating part and is connected byway of a line with a slip-ring disposed on the wheel hub on the insideof the brake; one of several stationary brushes slide on the slip-ringwhereby the slip-ring itself is arranged on the wheel hub exclusively onthe inside of a sealed-off space and is connected with the signaltransmitter by way of a cable on the inside of the wheel hub while thebrush or brushes are secured at the brake carrier with the aid of aone-piece plastic part which simultaneously contains means for guiding19 Claims, 2 Drawing Figures the cable.

E i L r I )/I 20 I7 27 m (I I 23 11 21 PATENTEDHAR 81973 $719,916 I 1 Ail.

I NVENTORS OTTO WORNER FRANZ BRUGGER ERWIN WELLER BY Cml q w; {twink vATTORNEYS SLIP-RING ARRANGEMENT ESPECIALLY FOR BRAKE SLIPPAGE CONTROLINSTALLATIONS OF MOTOR VEHICLES The present invention relates to aslip-ring arrangement, especially for brake force control systems inmotor vehicles for the transmission of electric signals from a rotatingpart to a stationary part, whereby a signal transmitter is arrangedpreferably centrally at the rotating part and is connected by way of aline with a slip-ring disposed on the wheel hub within a brake, on whichrun one or several stationary, elastically readjustable brushespreferably arranged at the brake carri- With such types of slip-ringarrangements considerable problems exist as regards the seal by reasonof the soiling customary at the vehicle wheel. One has attemptedtheretofore to solve these problems in that a separate slip-ring supportis mounted over an axle stub, to which a cable is led about the outsidefrom the central signal transmitter. The brushes slide on the slip-ringwhich are inserted in a sealing ring mounting. A cable again leads fromthe brushes to a separate passage in the brake carrier. This prior artarrangement is disadvantageous because, first of all, it does notproduce a good seal and, secondly, it is complicated in construction anddifficult in the assembly. Additionally, the externally extending cableis subjected to the influence of the centrifugal force so that undercertain circumstances there is a tendency to abrasion at the placeswhere it passes through stationary parts. The connecting places of thiscable are also unfavorably stressed by the centrifugal force.

The present invention is concerned with the task to avoid theaforementioned disadvantages. Consequently, a slip-ring arrangement isto be provided which produces an absolutely safe seal during continuousoperation over long periods of time, and which in the construction, themanufacture and the assembly is simple and inexpensive. The underlyingproblems are solved by the present invention with the arrangements ofthe type described above in that the slip-ring is arranged on the wheelhub exclusively on the inside of the sealed-off space and that it isoperatively connected on the inside of the wheel hub by way of a cablewith a contact-maker arranged in a central dead-end bore of the wheelhub, and in that the brush or brushes are secured at the brake carrierwith the aid of a unitary, one-piece plastic part whereby this plasticpart simultaneously contains the cable guidance.

The construction according to the present invention offers the advantagethat an absolute sealing tightness is achieved by the central cableguidance and the arrangement of the slip-ring. Additionally, thecentrifugal force on the cable is reduced. The brush mounting isconsiderably simplified so that-as seen from an overall point ofview-the slip-ring arrangement according to the present invention canbe. manufactured very easily and can be assembled very easily.

In a preferred embodiment of the present invention a support ring of anysuitable plastic material is laterally mounted over the wheel hub, whichis provided with at least one radially inwardly directed cam acting aslocking means against rotation whereby the metallic slip-ring isembedded in this support ring. The support ring may thereby also bemolded or castover the wheel hub, pressed over the wheel hub or mountedover the same in any other suitable manner. Similar considerations alsoapply for the embedding of the slip-ring itself into the support ring.

It is additionally proposed by the present invention that an inclinedbore extends from a recess at the wheel hub circumference correspondingto the cam of the support ring toward the central dead-end bore for theaccommodation of the transmission cable in the wheel hub interior.Naturally the connection of the cable to the slip-ring may also takeplace at any other appropriate place, i.e., for example, also outside ofthe aforementioned cam. It is particularly appropriate if the cable isthereby embedded in the support ring and is connected inside of thesupport ring with the slip-ring or slip-rings.

A further feature of the present invention resides in that the supportring together with the slip-ring is disposed sealed off on the inside ofa sleeve-shaped sealing-ring mounting, which is secured at one end inthe brake carrier and at the other end carries a seal. This seal then isappropriately disposed directly on the wheel hub.

A further proposal of the present invention resides in that the plasticpart receiving the brush is sealingly inserted into an opening of thesealing-ring mounting. The seal can thereby take place by means of anO-ring or in a similar manner. According to the present invention theplastic part receiving the brush engages with a lateral extension inanaperture at the brake carrier plate whereby the continuing cable issealingly inserted into this extension. Also in that case the insertionor installation can take place by molding or casting about the cable.Provision is furthermore made that the opening at the brake carrierplate is constructed approximately as radially disposed elongatedaperture through which the lateral extension of the plastic partprojects and that the plastic part is secured in this elongated apertureby means of a threaded connection. A metal insert is provided accordingto the present invention in the plastic part for this threadedconnection. This metal insert may also include the cable sheath forpurposes of tensional relief of the cable.

Accordingly, it is an object of the present invention to provide aslip-ring arrangement, especially for brake force control systems inmotor vehicles, which avoids by simple means the aforementionedshortcomings an drawbacks encountered in the prior art. I

Another object of the present invention resides in a slip-ringarrangement, intended in particular for brake force controlinstallations in motor vehicles which solves the problems as regardssealing and soiling in a most satisfactory manner.

A further object of the present invention resides in a slip-ringarrangement of the aforementioned type which not only produces a goodseal but is simple in construction and easy to install.

Still another object of the present invention resides in a slip-ringarrangement, especially for brake force control installations in motorvehicles, which minimizes the influence of the centrifugal force on thecable transmitting a signal from a rotating to a non-rotating part.

Still a further object of the present invention resides in a slip-ringarrangement for brake force control systems in motor vehicles whichexhibits an extraordinarily long length oflife combined with absolutesealing tightness.

These and other objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, one embodiment in accordance with thepresent invention, and wherein FIG. 1 isa partial axial cross-sectionalview through a slip-ring arrangement in accordance with the presentinvention, and

FIG. 2 is a cross-sectional view through the support ring and slip-ring,taken along line II II in FIG. 1.

Referring now to the drawing wherein like reference numerals are usedthroughout the two views to designate like parts, a conventionalcontact-maker 11 is arranged according to FIGS. 1 and 2 in the wheel hubcentrally thereof, which transmits the signals of a pulse transmitter 12of conventional construction and therefore not illustrated in detail.The wheel hub 10 carries in an otherwise known manner by means of aflange 13 the brake disc 14, not illustrated in detail, in the drum-likepart 15 of which is arranged the hand brake 16. A support ring 17 islaterally mounted directly on the wheel hub 10, which engages at oneplace (FIG. 2) by means of a cam 18 in a corresponding recess 19 at thewheel hub 10. The support ring 17, therefore, cannot rotate relative tothe wheel hub 10. A slip-ring 20 is embedded in the support ring 17. Thesupport ring 17 is disposed on the inside of a sleeveshaped sealing ringmounting 21 which at one end is secured in the brake carrier 22 and atthe other end carries a sealing ring generally designated by referencenumeral'23 of any conventional construction which abuts with its sealinglip directly at the wheel hub'10. The slip-ring 20 is therefore disposedon the inside of the sealed-off space.

An inclined bore 25 leads on the inside of the wheel hub 10 from acentral dead-end bore 25 in the wheel hub 10-in which is inserted thecontact-maker ll-up to the recess 19. A cable leads through thisinclined bore 25 from the contact-maker 11 to the slip-ring 20. Thecable end is soldered to the slip-ring 20 in a customary manner. In thismanner the cable inclusive its connecting places is arranged over itsentire length on the inside of the sealed off space.

An aperture 27 is provided in the sealing-ring mounting 21, into which'aplasticpart generally designated by reference numeral 28 and serving asbrush support is sealingly inserted by means of an O-ring 29. Aconventional springy brush re-adjusting mechanism of known constructionand therefore not illustrated in detail is arranged on the inside ofthis plastic part 28. The plastic part 28 includes a lateral extension30 by means of which itengages in an elongated aperture 31 at the brakecarrier 22. A radial extension at the plastic part 28 includes ametallic threaded brush 32. The plastic part 28 is secured in theelongated aperture 31 with the aid of the screw 33 and this threadedbush 32.

The further cable 34 is inserted into the lateral extension 30 of theplastic part 28 and is connected thereat with the brush arrangement.Also this connection is thereby sealed off absolutely. In order toachieve a tensional load. relief, it is also possible to insert theouter sheath of the cable 34 into the threaded bush 32 and, for example,to securely clamp the same thereat.

While we have shown anddescribed only one embodiment in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown'to those skilled in the art and we therefore do not wish to belimited to the details shown and described herein but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

What we claim is:

1. A slip-ring arrangement for transmitting electrical signals from arotating to a stationary part, in which a signal transmitter means isarranged at the rotating part and is operatively connected by way of acable with a slip-ring means disposed on a wheel hub on the inside of abrake means, and in which at least one brush means slides on theslip-ring means, characterized in that the slip-ring means is arrangedon the wheel hub exclusively inside of a sealed-off space means, in thatthe slip-ring means is operatively connected on the inside of the wheelhub by way of a cable with a contact means arranged in a substantiallycentral dead-end bore of the wheel hub, and in that the brush means issecured at a part of the brake means with the aid of a plastic part,said plastic part simultaneously containing cable guide means.

2. A slip-ring arrangement according to claim 1, characterized in thatthe signal transmitter means is arranged substantially centrally.

3. A slip-ring arrangement according to claim 1, characterized in thateach brush means is resiliently adjustable.

4. A slip-ring arrangement according to claim 1, characterized in thatthe plastic part is a unitary, onepiece element.

5. A slip-ring arrangement according to claim 1, characterized in thatthe part of the brake means at which the brush means is arranged is abrake carrier.

6. A slip-ring arrangement according to claim 1, characterized in thatseveralbrush means slide on the slip-ring means.

7. A slip-ring arrangement according to claim 1, characterized in thatthe slip-ring arrangement is used with a brake force control system ofmotor vehicles.

8. A slip-ring arrangement according to claim 1, characterized in that asupport ring means of plastic material is laterally mounted over thewheel hub, which includes at least one radially inwardly directed cammeans operable as rotation-preventing means, and in that the metallicslip-ring means is embedded in this support ring means.

9. A slip-ring arrangement according to claim 8, characterized in thatan inclined bore for the accommodation of the cable in the wheel hubinterior extends from a recess at the wheel hub circumference,corresponding to the cam of the support ring means, toward thesubstantially central dead-end bore.

10. A slip-ring arrangement according to claim 9, characterized in thatthe cable is embedded in the support ring means and is operativelyconnected onthe inside of the support ring means with the slip-ringmeans.

11. A slip-ring arrangement according to claim 10, characterized in thatthe support ring means is disposed together with the slip-ring means onthe inside of a sleeve-shaped sealing ring mounting means which issecured at one end at the part of the brake means and which carries atthe other end a seal means.

12. A slip-ring arrangement according to claim 11, characterized in thatthe plastic part receiving the brush means is inserted into an apertureof the sealingring mounting means.

13. A slip-ring arrangement according to claim 12, characterized in thatthe plastic part receiving the brush means engages with a lateralextension thereof into an aperture at a brake carrier plate and in thata further cable is sealingly inserted into said extension.

14. A slip-ring arrangement according to claim 13, characterized in thatthe aperture at the brake carrier plate is constructed as approximatelyradially disposed elongated aperture and the plastic part is secured insaid elongated aperture by a threaded connecting means.

15. A slip-ring arrangement according to claim 8, characterized in thatthe cable is embedded in the support ring means and is operativelyconnected on the inside of the support ring means with the slip-ringmeans.

16. A slip-ring arrangement according to claim 8, characterized in thatthe support ring means is disposed together with the slip-ring means onthe inside of a sleeve-shaped sealing ring mounting means which issecured at one end at the part of the brake means and which carries atthe other end a seal means.

17. A slip-ring arrangement according to claim 16, characterized in thatthe plastic part receiving the brush means is inserted into an apertureof the sealingring mounting means.

18. A slip-ring arrangement according to claim 16, characterized in thatthe plastic part receiving the brush means engages with a lateralextension thereof into an aperture at a brake carrier plate and in thata further cable is sealingly inserted into said extension.

19. A slip-ring arrangement according to claim 18, characterized in thatthe aperture at the brake carrier plate is constructed as approximatelyradially disposed elongated aperture and the plastic part is secured insaid elongated aperture by a threaded connecting means.

1. A slip-ring arrangement foR transmitting electrical signals from arotating to a stationary part, in which a signal transmitter means isarranged at the rotating part and is operatively connected by way of acable with a slip-ring means disposed on a wheel hub on the inside of abrake means, and in which at least one brush means slides on theslip-ring means, characterized in that the slip-ring means is arrangedon the wheel hub exclusively inside of a sealed-off space means, in thatthe slip-ring means is operatively connected on the inside of the wheelhub by way of a cable with a contact means arranged in a substantiallycentral dead-end bore of the wheel hub, and in that the brush means issecured at a part of the brake means with the aid of a plastic part,said plastic part simultaneously containing cable guide means.
 1. Aslip-ring arrangement foR transmitting electrical signals from arotating to a stationary part, in which a signal transmitter means isarranged at the rotating part and is operatively connected by way of acable with a slip-ring means disposed on a wheel hub on the inside of abrake means, and in which at least one brush means slides on theslip-ring means, characterized in that the slip-ring means is arrangedon the wheel hub exclusively inside of a sealed-off space means, in thatthe slip-ring means is operatively connected on the inside of the wheelhub by way of a cable with a contact means arranged in a substantiallycentral dead-end bore of the wheel hub, and in that the brush means issecured at a part of the brake means with the aid of a plastic part,said plastic part simultaneously containing cable guide means.
 2. Aslip-ring arrangement according to claim 1, characterized in that thesignal transmitter means is arranged substantially centrally.
 3. Aslip-ring arrangement according to claim 1, characterized in that eachbrush means is resiliently adjustable.
 4. A slip-ring arrangementaccording to claim 1, characterized in that the plastic part is aunitary, one-piece element.
 5. A slip-ring arrangement according toclaim 1, characterized in that the part of the brake means at which thebrush means is arranged is a brake carrier.
 6. A slip-ring arrangementaccording to claim 1, characterized in that several brush means slide onthe slip-ring means.
 7. A slip-ring arrangement according to claim 1,characterized in that the slip-ring arrangement is used with a brakeforce control system of motor vehicles.
 8. A slip-ring arrangementaccording to claim 1, characterized in that a support ring means ofplastic material is laterally mounted over the wheel hub, which includesat least one radially inwardly directed cam means operable asrotation-preventing means, and in that the metallic slip-ring means isembedded in this support ring means.
 9. A slip-ring arrangementaccording to claim 8, characterized in that an inclined bore for theaccommodation of the cable in the wheel hub interior extends from arecess at the wheel hub circumference, corresponding to the cam of thesupport ring means, toward the substantially central dead-end bore. 10.A slip-ring arrangement according to claim 9, characterized in that thecable is embedded in the support ring means and is operatively connectedon the inside of the support ring means with the slip-ring means.
 11. Aslip-ring arrangement according to claim 10, characterized in that thesupport ring means is disposed together with the slip-ring means on theinside of a sleeve-shaped sealing ring mounting means which is securedat one end at the part of the brake means and which carries at the otherend a seal means.
 12. A slip-ring arrangement according to claim 11,characterized in that the plastic part receiving the brush means isinserted into an aperture of the sealing-ring mounting means.
 13. Aslip-ring arrangement according to claim 12, characterized in that theplastic part receiving the brush means engages with a lateral extensionthereof into an aperture at a brake carrier plate and in that a furthercable is sealingly inserted into said extension.
 14. A slip-ringarrangement according to claim 13, characterized in that the aperture atthe brake carrier plate is constructed as approximately radiallydisposed elongated aperture and the plastic part is secured in saidelongated aperture by a threaded connecting means.
 15. A slip-ringarrangement according to claim 8, characterized in that the cable isembedded in the support ring means and is operatively connected on theinside of the support ring means with the slip-ring means.
 16. Aslip-ring arrangement according to claim 8, characterized in that thesupport ring means is disposed together with the slip-ring means on theinside of a sleeve-shaped sealing ring mounting means which is securedat one end at the part of the brake means and which carries at the othErend a seal means.
 17. A slip-ring arrangement according to claim 16,characterized in that the plastic part receiving the brush means isinserted into an aperture of the sealing-ring mounting means.
 18. Aslip-ring arrangement according to claim 16, characterized in that theplastic part receiving the brush means engages with a lateral extensionthereof into an aperture at a brake carrier plate and in that a furthercable is sealingly inserted into said extension.